Stator construction for compressors



June 5, 1956 A. HAsBRoUcK ET AL 2,749,026

STATOR CONSTRUCTION FOR cOMPREssORs June 5, 1956 A. HAsBRoUcK ET AL2,749,026

STATOR CONSTRUCTION FOR COMPRESSORS 2 Sheets-Sheet 2 Filed Feb. 27 1951STATOR CONSTRUCTION FOR COMPRESSORS Augustus Hasbrouck, Middletown, andByron H. Shinn,

Rockville, Conn., assignors to United Aircraft Corporation, EastHartford, Conn., a corporation of Delaware Application February 27,1951, Serial No. 212,974

9 Claims. (Cl. 2210-122) The present invention relates to axial owcompressors and particularly to an arrangement for supporting the statorvanes in position.-

It has been found that the individual vanes of each row of stator vanesin an axial flow compressor must be securely supported at their outerends in order to keep to a minimum the deflection of the vanes resultingfrom the pressures acting thereon. It is apparent that the thicker thesupport at the outer end of the vane the more securely the vane will beheld against dellection. Accordingly, one feature of the invention is ashroud construction which will provide a wide base for the support ofthe vane at the same time producing a supporting structure which willhave a low weight.

In accordance with this feature, the shroud is made up in cross section,in the form of an open box, the top and bottom of which both receive andsupport the end of the vane, and being spaced apart provide a broadersupport for the vanes. The resulting structure is the equivalent of athicker sheet than it is possible to pierce with a punch of the vanecross section. Another feature of the invention is the assembly of thisshroud.

It has been customary to provide openings through the supporting shroudfor the vanes in which the vanes yare positioned in assembly. Suchopenings are frequently provided by a punching operation. For a securefit of the vane within the opening in the shroud it is necessary thatthe punch conform almost exactly to the shape of the vane. Even then,however, the tolerances and variations in shape of both punch and vanemay result in openings which will not receive the vane, or which willnot securely hold the vane without some looseness. A feature of thisinvention is the perforation of the shroud by the use of the vane itselfas the punch. The vane remains in position after the punching operationsuch that the resulting opening in the supporting shroud must ofnecessity conform exactly to the shape of the vane.

Where the shroud is box-shaped, as above mentioned, alignment of thepre-punched vane receiving openings in the inner and outer rings of theshroud presents a problem since a slight misalignment of the openingswould result in serious misalignment of the inner ends of the vanes. Afurther feature of the invention is the elimination of the alignmentproblems by the punching and assembly of the vanes and shrouds in asingle operation.

Other objects and advantages will be apparent from the specification andclaims, and from the accompanying drawings which illustrate anembodiment of the invention.

Fig. 1 is a longitudinal sectional view through a multistage axial flowcompressor with the vanes held by a box-type shroud.

Fig. 2 is a fragmentary sectional view on a larger scale showing thesupporting shroud for one row of vanes and the adjacent spacer ring.

Fig. 3 is a fragmentary sectional view showing apart of the shroud ringwith some of the vanes assembled.

partially v United States Patent 2,749,026 Patented June 5', 1956 ICCFig. 4 is a fragmentary sectional view at right angles to Fig. 3.

Fig. 5 is a view similar to Fig. 3, showing a further step.

Fig. 6 is a fragmentary sectional view similar to Fig. 4 with the outershroud ring assembled.

Fig. 7 is a fragmentary sectional view on a larger scale than Fig.A l,showing the diaphragm construction. 1

Fig. 8 is a fragmentary sectional view along line 8-8 of Fig. 7.

With reference first to Fig. 1 the invention is shown in a multistageaxial ow compressor in which a housing 2 is made up of a centralsubstantially cylindrical element 4 having stiifening ribs 5 thereon andend rings 6 and 8 bolted to the central element. The housing supportsrows` of axially spaced stator vanes 10 projecting inwardly from thehousing and alternating with rows of blades 12 on the rotor 14.

The rotor construction is not a part of the present invention. Theparticular rotor construction shown comprises a number of axially spaceddiscs 16 each having one row of blades 12 mounted on its periphery, thediscs being spaced apart by suitable spacer tubes 18 arranged' A numberof through bolts 22 extending through the' series of discs and throughthe spacer tubes from one end of the rotor to the other secure the discstogether in predetermined spaced relation and also secure the end bells24 and 26 which support the rotor in bearings, not shown.

Each of the rows of vanes 10 is supported at its outer end by a boxshroud 28 in the form of a ring and carries at its inner end a diaphragm30, the inner end of which supports a sleeve 31 cooperating with sealingiins 32 on the outer surfaces of the cylinders 20 on the rotor. The boxshrouds or box shroud rings of successive vane rows are spaced apart byspacers 34 which function not only to hold the box shrouds inpredetermined spaced axial relation to each other but also haveprojecting lugs 36 which pilot the spacer rings and box shrouds withinthe outer housing and support the shrouds in spaced relation to theouter housing. It will be noted that the element 4 of the outer housinghas its cylindrical inner surface formed as a succession of steppedcylindrical surfaces 38 gradually increasing in diameter toward one endof the housing to provide for assembly of the housing over a built upassembly of stator rings and spacers.

As best shown n Fig. 2 each box shroud is made up of an innersubstantially flat ring 40 and an outer similar flat ring 42 throughboth of which the vanes lil extend. The rings are spaced apart radiallyand are held in predetermined spaced relation by spacers 44 and 46welded or otherwise securely attached to the opposite edges of the rings40 and 42. The spacers 44 and 46 are preferably U-shaped, as indicated,to provide laterally open grooves 48 to receive cooperating tongues 50on the spacer rings 34.

Each of the spacer rings 34 has an inner surface 52 so spaced inreference to the tongues 50 that when the spacer rings and box shroudsare assembled the surface 52 on the spacer ring will form a continuationof the inner surfaces 54 of the adjacent box shrouds to provide a smoothsurface for the flow of the fluid being compressed.

The outer ring 42 and the adjacent portion of the spacers 44 and 46 arenotched as at 56 to receive the projecting lugs 36 on the spacer ringsthereby holding the box shrouds and spacer rings against relativerotation; It will be apparent that the lugs 36 are so dimensioned thatthey will provide a close fit with the cooperating cylindrical surface38 of the outer housing thereby functioning to pilot the spacer ringsand also the box.

shrouds accurately within the housing. It may be noted in connectionwith Fig. l that the endmost spacer ring 58 has a projecting radialflange 60 which is engaged by the same bolts 62 that hold the mainelement 4 and end section 8 of the outer housing together therebysupporting this spacer ring in such a manner that it cannot rotate.

In the assembly of the stator vanes in the box shroud the entire row ofvanes are first punched through the inner ring 40, as best shown in Fig.4. In performing this punching operation the outer end of the bladeitself acts as the punch and the device is so set up that a suitableclamp 64 engages each blade and drives it through the ring 40, thelatter being backed up by a die 66 of conventional construction. It maybe advantageous to cut back the trailing edge of the vane as shown at67, to improve the punching action.

The vanes having been punched through the inner ring 40, one of thespacers 44 or 46 is attached to the ring 40 and the outer ring 42 isattached to the spacer thereby i leaving the opposite edges of the rings40 and 42 open to permit the insertion of fingers 68 which space theinner and outer rings and also support the inner ring while each vane isbeing forced through the outer ring 42. Obviously during the punching ofthe outer ring the latter is backed up by a die such as the die 66 or asimilar die which will support the material of the ring while the vaneis forced through it. The row of vanes having been punched through theouter ring the other spacer 46 is secured in position and the outershroud ring assembly with the vanes is completed.

With this arrangement, the holes in the rings 40 and 42 are inevitablyin precise radial alignment and of necessity accurately fit the vane,having been punched by the vane itself. The vanes remain in position inthe shroud rings after the punching operation, and are retained thereinsolely by a frictional fit with the shroud rings. The holes made by eachvane necessarily correspond in transverse cross-sectional shape and areato the vane therein, and the vanes are securely held and supported byeach of the inner and outer rings such that there is no looseness andthe only deflection that will occur when the row of vanes is loaded isthe deflection resulting from the load itself applied to the vanesrather than any defiection resulting from looseness between the parts.

At their inner ends, the vanes are supported in alignment with eachother by the diaphragm 30 which, to permit ease of assembly over theinner ends of the vanes, is made up in two parts. One part 70 is in theform of a ring consisting of a disc or radial flange having at its outerperiphery a cylindrical or axially projecting flange 72. This flange isoffset at a point spaced from the disc by a dimension approximately halfof the axial dimension of the vane to form a shoulder 85 engaginglaterally with a radial surface 84 on the vane as shown. The flange 7,2also has an outer surface 73 engaging endwise with the vanes adjacent totheir trailing edges (it will be understood that the row of vanes may benotched at their inner ends after assembly in the outer shroud toprovide the precision surfaces engaged by surfaces 73 and 85). Thesecond part 75 of the diaphragm consists of a cylindrical portion orring 76 and a radial flange 78. The ring 76` has a row of notches 74,Fig. S, corresponding approximately in shape to the upstream half of thecompressor vanes and is fitted over the inner ends of the vanes as bestshown in Fig. 8. The radial flange 78 abuts the surface of the radialflange on the part 70.

A s shown, each vane has a notch 82 which substantially corresponds inshape to the surface of the flange 72 and is engaged thereby in theassembly of the parts.

The notch 82 is preferably cut back adjacent to the corner of the notchto provide two distinct surfaces for engagement respectively with thesurfaces 73 and 85 'on the flange 72. The vanes and the outer surface ofthe ange 72 have cooperating angled surfaces 8 6 and 87 to lit provide awedging action when the parts and 75 are assembled.

The second part having been assembled in position it may be welded orotherwise secured and attached to the disc 70. The inner end of radialflange 70 may have attached thereto a sleeve 31 which cooperates withthe sealing fins 32. i

The stator ring has been described with the sleeves and spacers for theouter shroud forming, when welded together, a shroud ring segment whichis a circumferentially unsplit part. It will be understood that the samepart may be made up of two or more ring segments each forming only apart of a complete circle but together forming a complete shroud ring.

In the assembly of the compressor, it has been found desirous in certaininstances to assemble the rotor as a complete unit prior to its assemblywithin the stationary parts of the compressor. In this event, it isnecessary that the stator vane rings be split for positioning over inerotor, and with the stator construction above described, it has beenfound desirable to split the stator rings after the complete assembly ofthe stator vanes in the box shrouds in order to maintain concentricity.Thus in assembly of the compressor the rotor is supported with its axisvertical and with the downstream end of the rotor at the bottom. Thesplit halves of the stator rings are then placed successively inposition. The spacer rings 34 are not split and function to hold thestator rings in predetermined relation around the rotor in such a mannerthat the entire series of stator vanes and box shronds with thealternating spacer rings may be assembled around the rotor before theouter housing is placed in position. Subsequently the housing is placedin position and the several parts fastened together.

It is to be understood that the invention is not limited to the specificembodiment herein illustrated and decribed, but may be used in otherways without departure from its spirit as defined by the followingclaims.

We claim:

l. In a stator construction for a compressor, a row of radiallyextending stator vanes, and a ring segment engaging with and supportingthe outer ends of said vanes, said ring segment including spaced apartsubstantially concentric sleeve segments and means by which saidsegments are secured together, said sleeve segments having alignedopenings therein in which the vane ends are located, the openingsexactly tting the shape of the vane therein, said vanes being retainedin the ring segments solely by the fit between the vanes and theopenings in the ring segments.

2. in a stator construction for a compressor, a row of radiallyextending stator vanes, and a ring segment engaging with and supportingthe outer ends of said vanes, said ring segment including spaced apartsubstantially concentric sleeve segments and a spacer between adjacentedges of the sleeves to hold the sleeves in predetermined relation, theends of the vanes extending through both sleeves, said spacer having acircumferentially extending groove therein for use in alignment of thering segments making up a complete row of vanes.

3. A compressor` construction including a housing having a cylindricalinner surface, a number of rows of stator vanes each row having an outervane supporting shroud ring positioned within the housing in spacedrelation thereto and spacer rings located between the shroud rings foradjacent vane rows for maintaining the predetermined axial spacingbetween the rows of vanes, each of said spacer rings` having pilotingsurfaces engaginz,v with the cylindrical surface of the housing, andhaving means engaging with the adjacent shroud rings for supporting theentire periphery of each of said adjacent shroud rings out of contactwith and in spaced relation to the housing.

4. A compressor construction including a housing having a cylindricalinner surface, a number of rows of stator vanes each row having an outervane supporting shroud ring positioned within the housing in spacedrelation thereto and spaced and spacer rings located between the shroudrings for adjacent vane rows for maintaining the predetermined axialspacing between the rows of vanes, each of said spacer rings havingpiloting surfaces engaging with the cylindrical surface of the housing,and having means engaging with the adjacent shroud rings for supportingthe entire periphery of each of said adjacent shroud rings in spacedrelation to and out of contact with the housing, said piloting surfacesincluding projecting lugs on the spacer ring having outer surfacesfitting within and engaging with the cylindrical inner surface of thehousing.

5. A compressor construction including a housing having a cylindricalinner surface, a number of rows of stator vanes each row having an outervane supporting shroud ring positioned within the housing, in spacedrelation thereto, each shroud having a lateral groove therein and spacerrings located between the shroud rings for adjacent vane rows formaintaining the predetermined axial spacing between the rows of vanes,each of said spacer rings having piloting surfaces engaging with thecylindrical surface of the housing, and having means engaging with theadjacent shroud rings for supporting the entire periphery of each ofsaid adjacent shroud rings in spaced relation to and out of contact withthe housing, said last means being in the form of laterally projectingtongues engaging in the grooves provided in the shroud rings.

6. In a stator construction for a compressor, a row of radiallyextending stator vanes, means engaging with and supporting said vanes attheir outer ends, and a shroud assembly for the inner ends of saidvanes, said shroud assembly including a ring having notches therein toreceive the leading edges of the vanes and a cooperating ring adapted toengage with the inner ends of the vanes adjacent their trailing edgesfor holding them securely in the rst ring, and means securing said ringstogether.

7. In a stator construction for a compressor, a row of radiallyextending stator vanes, means engaging with and supporting said vanes attheir outer ends, and a shroud assembly for the inner ends of saidvanes, said shroud assembly including a ring having notches therein toreceive the leading edges of the vanes and a cooperating ring adapted toengage with the inner ends of the vanes adjacent their trailing edgesfor holding them securely in the iirst ring, each of said rings having aradial ange, and said radial flanges extending in close relation to eachother, and means attaching said anges together.

8. In a stator construction for a compressor, a row of radiallyextending stator vanes, and a ring segment engaging with and supportingthe outer ends of said vanes, said ring segment including spaced apartsubstantially concentric sleeve segments and means by which saidsegments are secured together, and means including a spacer membersnugly litting between the sleeve segments at one side of the vanes andsecured to said sleeve segments, said sleeve segments having alignedopenings therein in which the vane ends are located, the openingsexactly fitting the shape of the vane therein, said vanes being retainedin the ring segments solely by the tit between the vanes and theopenings in the ring segments.

9. In a stator construction for a compressor, a row of radiallyextending stator vanes, and a ring segment engaging with and supportingthe outer ends of said vanes, said ring segment including spaced apartsubstantially concentric sleeve segments and means securing said sleevesegments together to prevent relative movement therebetween, said sleevesegments having radially aligned vanepunched holes therein forming pairsof holes with one hole of each pair in each sleeve segment, the outerend of each vane extending through one pair of said holes and supportedby both sleeve segments, the holes of each pair being punched by thevane therein, and corresponding in transverse cross-sectional shape andarea to the vane therein, whereby the outer end of said vane is securelyretained in said sleeve segments solely by a frictional tit therewith.

References Cited in the file of this patent UNITED STATES PATENTS1,717,203 Gottschalk June 11, 1929 2,264,877 Haigh Dec. 2, 19412,327,259 Gay Aug. 17, 1943 2,350,310 Dahlstrand May 30, 1944 2,373,558Haigh Apr. 10, 1945 2,442,420 Lindvall June l, 1948 2,467,121 FerrisApr. 12, 1949 2,543,355 Davis Feb. 27, 1951 2,557,898 Thompson June 19,1951 2,606,741 Howard Aug; 12, 1952 2,610,786 Howard Sept. 16, 19522,640,319 Wislicenus June 2, 1953 FOREIGN PATENTS 26,979 Great Britain1903 622,895 Great Britain May 9, 1949

